Coyote Point Systems E350GX, Руководство по установке и администрированию

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Chapter 6: Administering Virtual Clusters
170 Equalizer Installation and Administration Guide
Unquiescing a Server When Server Count is Low
Let’s say we have a cluster that has three servers,
sv00
,
sv01
, and
sv02
:
• We want
sv00
and
sv01
to actively serve traffic, and
sv02
to have the
quiesce
option enabled while the
other two are running.
• If one (or both) of the active servers becomes unavailable, we want to disable the
quiesce
option on
sv02
so it starts serving traffic.
• Once the original two active servers are available again, we want to quiesce the third server.
The above can be accomplished by constructing two Smart Events:
Event 1
: If there are less than two servers active, unquiesce
sv02
and print a log message.
Event 2
: If there are three servers active, quiesce
sv02
and print a log message.
To create
Event 1
, do the following:
1. Right-click on the cluster name in the left frame and select
Add Event
from the popup menu.
2. Type a
Name
for the event, such as
unquiesce-sv02
, or accept the default. Click the Next icon (
>
) to open the
Event Trigger
expression editor.
3. In the
operators
field, click on the following controls:
a.
active_servers
b. the ‘less than’ operator (
<
).
c.
numeric
The
expression workbench
field should now look like this:
4. In the
expression workbench
field, click on the drop-down arrow shown in the blank parameter. Type ‘
2
’ into
the
numeric value
text box and then click
accept
.
5. At the top of the
Add New Event
popup window, click the Next icon (
>
). This displays the
Event Action
editor:
6. In the
functions
field, click on
unquiesce
.
7. In the
expression workbench
field, click on the drop-down arrow next to
unquiesce
. Select
sv02
in the popup
dialog and click
accept
.
8. In the
operators
field, click on
&&
.
9. In the
functions
field, click on
log
.
10. In the
expression workbench
field, click on the drop-down arrow next to
log(
““
)
. Type the following into the
message text box that appears:
There are fewer than two servers active. sv02 has been unquiesced.